Vision test for chjldren use of symbols

British Journal of Ophthalmology (Impact Factor: 2.98). 07/1965; 49(6):312-4. DOI: 10.1136/bjo.49.6.312
Source: PubMed
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    • "Each eye was tested separately and eye testing order was counterbalanced. Participants who were unable to name letters were assessed with the Kay picture test (Kay 1983) or Ffooks symbols (Ffooks 1965) which involve identifying and matching pictures or shapes. Any participants who wore glasses kept them on while visual acuity was tested. "
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    ABSTRACT: Evidence of atypical perception in individuals with ASD is mainly based on self report, parental questionnaires or psychophysical/cognitive paradigms. There have been relatively few attempts to establish whether binocular vision is enhanced, intact or abnormal in those with ASD. To address this, we screened visual function in 51 individuals with autistic spectrum disorder and 44 typically developing individuals by measuring visual acuity, stereoacuity, convergence, divergence, ocular motility, incidence of strabismus and integrity of the optokinetic response. The data suggest that many aspects of vision, including visual acuity, are unaffected in ASD, but that convergence is an aspect of visual function that merits further research in those with ASD.
    Journal of Autism and Developmental Disorders 03/2009; 39(7):965-75. DOI:10.1007/s10803-009-0705-8 · 3.06 Impact Factor
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    • "Various VA charts with easy-torecognize symbols have so far been used (Ffooks 1965; Weiss 1973) but many of them have drawbacks: (1) the minimal angle of resolution (MAR) of such symbols cannot be specified; (2) the dimensions of the symbols do not geometrically progress from line to line and, as VA is not assessed using a logarithmic scale, it is not possible to use parametric statistical tests to evaluate the results; (3) the distances between the symbols and lines do not conform to international rules for the control and standardization of contour interactions (Atkinson et al. 1986; Fern et al. 1986; Manny et al. 1987; Paliaga 1987). Furthermore, as the charts do not have a standardized protocol defining when the test should be concluded (termination rules) or how VA should be quantified, data collected by such charts show wide interoperator variability. "
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    ABSTRACT: The aim of this study was to assess the feasibility of a visual acuity (VA) test using the Lea Symbols 15-line folding distance chart and its diagnostic validity in detecting VA deficiency in preschool children. A group of 149 children aged 38-54 months underwent VA examination performed with the Lea 15-line folding optotype at a distance of 3 metres, according to a test protocol described in the Methods section. After the VA test, a complete ophthalmological examination, including cycloplegic retinoscopy, a cover test and examination of the anterior and posterior segments, was performed on each child in order to detect any VA-threatening ocular abnormality. The Lea Symbols test's sensitivity, specificity, positive and negative likelihood ratios (LR +, LR -) and the receiver operating characteristic (ROC) curve were calculated by means of standard procedures using each VA level of the chart from 0.1 to 1 (1-0 logMAR) as a cut-off point. The Lea Symbols test could be successfully used in 95.9% of the population. The most useful cut-off points for screening preschool children were found to be 0.8 (LR + 5.73, LR - 0.05) or 0.63 (LR + 11.7, LR - 0.23). The Lea Symbols test proved to be clinically useful in detecting VA deficiency in preschool children. The choice between the two best performing cut-off levels should be made according to the expected cost-effectiveness of the screening programme.
    Acta Ophthalmologica Scandinavica 01/2007; 84(6):807-11. DOI:10.1111/j.1600-0420.2006.00668.x · 1.85 Impact Factor
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    Transactions of the American Ophthalmological Society 02/1967; 65:544-90.
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